Grinding wheel



June 12, 1956 G. BALDWIN 2,749,685

GRINDING WHEEL Filed June 30, 1955 F i g 1 Pi g E3 INVENTOR.

GEORGE BALD WIN 14 TTO/PNEYS.

United States Patent GING WHEEL George Baldwin, Dayton, Ky., assignor to The Cincinnati Milling Machine (10., Cincinnati, Ohio, a corporation of Ohio Application June 30, 1955, Serial No. 519,282

7 Claims. (Cl. 51-209) This invention relates to improvements in grinding wheel structures and a novel and improved process of constructing same.

One of the objects of the present invention is the povision of a novel and improved process for efficiently and economically producing grinding wheels and particularly those which are known in the trade as cup wheels.

Another object of the invention is the provision of a novel and improved combination wheel structure which will provide greater strength to the wheel when in use and facilitate proper safe clamping of the same on a grinding wheel spindle.

A further object of the invention is the provision of an improved grinding machine and process of producing same which will minimize the wheel forming operations while insuring a proper positioning of the wheel when in use.

An additional object of the present invention is the provision of an improved combination wheel embodying an abrasive portion and an integrated safety backing and wheel breakage minimizing mounting portion having properly related bore and base sections for locating and positioning the wheel in a machine.

A further object of the invention is the provision of a structure of this character in which there is provided in connection with an abrasive wheel integrated or intimately associated wheel positioning and clamp engaging portions which may have slight inherent yield or resiliency to facilitate proper positioned clamping of the wheel in a machine with adequately distributed clamping pressure tending to minimize liability of damage or cracking of a wheel in connection with such clamping procedures.

Other objects and advantages of the present invention should be readily apparent by reference tothe following specification, considered in conjunction with the accompanying drawings forming a part thereof, and it is to be understood that any modifications may be made in the exact structural details there shown and described, within the scope of the appended claims, without departing from or exceeding the spirit of the invention.

Figure 1 is an elevation of an initially formed wheel blank.

Figure 2 is a similar view of a shaved or shaped blank as prepared for the firing or hardening of the wheel.

Figure 3 is a view in elevation of one form of nonmetallic bushing member for use in connection with the abrasive unit shown in Figure 2.

Figure 4 is a view of the assembled bushing unit and abrasive section.

Figure 5 is a vertical section showing a grinding wheel in its finished form.

Figure 6 is a section of semi-finished wheel unit mounted for finishing the interior of the cone portion thereof.

Figure 7 is a similar view illustrating the manner of mounting of the Wheel for formation of the concentric outer taper face thereof, and

Figure 8 is a plan view of the completed article.

It will be understood that the present invntion is ap- Patented June 12, 1956 plicable for utilization in connection with grinding wheels of various types, but for purposes of illustration has been particularly illustrated in connection with the production of cup type grinding wheels.

In the manufacture of such Wheels according to the present invention a tubular or ringlike block 10 of suitable abrasive material is first formed or molded into shape as shown in Figure 1, having a central bore as indicated at 11. Such a ring or disc can be formed from a mix of abrasive grains and bond, with a dextrine binder for holding the material in its initially shaped condition, while the suitable vitrified or other bond when subjected to proper heating or firing and annealing processes will unite the abrasive grains or particles as a solid integrated grinding wheel. In the carrying out of the present process the initial ring, as indicated in Figure 1 having been formed and baked sufficiently to harden the dextrine binder but prior to the final backing for solidification of the Wheel by the vitrified binder is shaped as indicated in Figure 2 by a suitable cutting or shaving operation.

This forms a central frusto-conical recess as indicated by the dotted lines 12 and 13 in Figure 2 in proper circumscribing relation to the bore 11. The wheel having been thus formed into a semi-finished condition as to shape, while in an easily workable uncured state, is then fired properly to harden same, the bore at 11 having been produced at right angles to the base 14 on which the ring 10 rests during the said forming portion.

In Figure 3 there has been shown a hardened mount to be integrated with the ring or disc having the base section or flange 15 from which rises the bush 16 having the central bore 17. This may be of suitable plastic or composition material, a rubberized plastic such as Kralastic having proved very effective as to supportin and securing characteristics.

In formation of the present improved grinding wheel the cup is turned upside down or with its cone section providing a support and the bush 16 is pressed into the bore 11 in close interfitting engagement therewith. Prior to such assembly either the bushing and flange or the area of the wheel to be engaged by these parts, or both, is coated with a suitable adhesive which may be of known commercial type having viscous flow characteristics which will permit it to flow into and become embedded in and physically interlocked with the minute interstices of the wheel grain material and desirably including a solvent of the volatile type which will tend to slightly attack or soften the face of the plastic mount to an extent to become homogeneously united therewith. As the amount or layer of such adhesive material is preferably relatively slight so that the position and relationship of the bushing and wheel body 10 are determined by the interfitting of these parts, the area of location of the adhesive at the junction of the parts has been indicated by a thickening of the line of division 18 between the wheel and bushing as shown in sectional views 5, 6, and 7.

Theparts having been thus united into an integral wheel blank structure with the bushing forming with the basal flange 15 of the mount forming a smooth plain surface for engagement with a collar or the like on a grinding wheel spindle mount, the wheel is then faced or shaped as by cutting or grinding into final commercial form. as indicated in Figures 6 and 7. During the several final shaping operations, the flange 15 is utilized as a position determinant or base and the bore 17 of the bushing portion as an axis determinant during stock removing generation of the disc into its frusto-conical cup form. Advantageously, the bushing 16 may be mouned on a rotatable centering spindle 19 with the basal flange 15 resting against a shoulder on the spindle and with the circumscribing face of a self-centering chuck member 20, gripping the exterior of the cylindrical member 10. In this position the inner face 21 and the front face 22 are shaped by cutting or truing to produce final finished surfaces at 21, 22 and 23 respectively in proper parallelism with the end or free face of the flange 15 and concentric-with the bore 17 of the bushing.

These surfaces having been completed, the combination wheel is then mounted on a second spindle 24 in reverse position with the bore 17 of the bush fitting on the stud portion 25 of the spindle 24 and the wheel unit clamped in position by nut 26. With the parts in this position, the outer periphery of the wheel is trued to remove the portion of material indicated by the dotted lines at 27 in Figure 7 forming a final concentric outer frusto-conical wheel surface 23 concentric with the bore of the bush and the other surfaces produced on the wheel with the bore 1'7 and flange 15 as positioned determinates.

For completion of the wheel a ring or washerlike cushioning or clamp engaging member 29 preferably of semi rigid but yieldable material may then be secured within the conical recess of the Wheel. This member, as indicated, may be utilized to carry size, source or other identifying indicia as respects the wheel and is preferably of size so that its inner ring just circumscribes the outer diameter of the bushing 15. This presents the advantage that in clamping the wheel in position on a grinding machine the clamping member of the grinding machine may react directly against the member 29 and thence on to the body of the wheel itself, firmly pressing the wheel against the integrated basal flange 15 but insuring the clamping action being exerted against the wheel and basal flange rather than against the upper face of the bushing 16. The final appearance of the completed cup Wheel structure of the present invention has been shown in Figure 8.

What is claimed is:

l. The process of producing a grinding wheel consisting in forming a ringlike abrasive blank having a basal face and a central bore, mounting a plastic bush within the bore having a basal flange overlying the basal face of the ring, securing the parts together, and shaping the abrasive portion of the wheel into frusto-conical form in concentric relation with the bushing and with its axis extending at right angles to the basal flange of said bushmg.

2. The process of producing a grinding wheel consisting in forming a ringlike abrasive blank having a basal face and a central bore, mounting a plastic bush within the bore having a basal flange overlying the basal face of the ring, securing the parts together with an interposed adhesive, and shaping the abrasive portion of the wheel into frusto-conical form in concentric relation with the bushing and with itsaxis extending at right angles to the basal flange of said bushing.

3. A cup grinding wheel comprising a plastic unit having a basal flange and an upstanding bushing portion, an abrasive disc having a central aperture receiving the bushing and a plane surface engaging the flange, and an interposed viscous cementing medium interposed between said disc and said plastic member, said adhesive physically and adhesively interfitting with and engaging the grain and bond of the abrasive disc and initially containing a solvent reacting on the plastic member whereby the adhesive will homogeneously unite therewith.

4. A grinding wheel comprising a plastic unit having a basal wheel surface engaging flange providing a wheel reinforcing portion and a grinding wheel spindle engaging seat, said unit having a bushing with an inner bore for engagement on a grinding wheel spindle and a concentric outer surface for reception of an abrasive disc, an abrasive disc having a central aperture snugly receiving said concentric outer surface of the bushing and having a face fitting against said flange, and viscous cementing medium interposed between said disc and said plastic member, said adhesive physically and adhesively interfitting with and engaging the grain and bond of the abrasive disc and initially containing a solvent reacting on the plastic member whereby the adhesive will homogeneously unite therewith.

5. A cup grinding wheel comprising a plastic unit having a basal wheel surface engaging flange providing a wheel reinforcing portion and a grinding wheel spindle engaging seat, said unit having a bushing with an inner bore for engagement on a grinding wheel spindle and a concentric outer surface for reception of an abrasive disc, a cup-shaped abrasive disc having a central aperture snugly receiving said concentric outer surface of the bushing,

and having a face fitting against said flange, a viscous cementing medium interposed between said disc and said plastic member, said adhesive physically and adhesively interfitting with and engaging the grain and bond of the abrasive disc and initially containing a solvent reacting on the plastic member whereby the adhesive will homogeneously unite therewith, and a clamp engaging ring secured to the wheel at the base of the cup in opposed relation to said basal flange.

6. A cup grinding wheel comprising a plastic unit having a basal wheel surface engaging flange providing a wheel reinforcing portion and a grinding wheel spindle engaging seat, said unit having a bushing with an inner bore for engagement on a grinding wheel spindle and a concentric outer surface for reception of an abrasive disc, a cup-shaped abrasive disc having a central aperture snugly receiving said concentric outer surface of the bushing and having a face fitting against said flange, a viscous cementing medium interposed between said disc and said plastic member, said adhesive physically and adhesively interfitting with and engaging the grain and bond of the abrasive disc and initially containing a solvent reacting on the plastic member whereby the adhesive will homogeneously unite therewith, and a clamp engaging ring secured to the wheel at the base of the cup in opposed reiation to said basal flange, said ring having its inner periphery circumscribing the outer surface of the bushing whereby to transmit applied clamping action directly against the abrasive disc in the direction of said flange mechanically to secure the disc in position on the bush.

7. The process of producing a cup-shaped grinding wheel consisting in forming an uncured disc, from a mix containing abrasive grain and a fusible binder, in the shape of a recessed disc having a central bore, curing the disc, cementing to the cured disc a support member having a flange fitting against one side of the disc and a bushing portion integral with the flange and fitting the central bore, and subsequently utilizing the flange as a parallelism determinant and the bushing as an axis determinant for shaping the disc into frusto-conical cup form.

References Cited in the file of this patent UNITED STATES PATENTS 162,010 Bannister Apr. 13, 1875 2,187,350 Kuzmick Jan. 16, 1940 2,542,154 Mesirow Feb. 20, 1951 

